The invention relates to a motor vehicle with an air-conditioning system which contains an environmentally compatible, non-flammable and non-toxic circulating medium.
For the air-conditioning of the passenger compartment of motor vehicles, use has hitherto been made of compression systems which contain fluorocarbons or chlorofluorocarbons as the circulating medium. From the standpoint of environmental compatibility, more and more emphasis is being placed on the search for alternative media which make very little contribution, if any, to a greenhouse effect. A compression system containing CO.sub.2 as the circulating medium is economical and environmentally neutral. Because of the high vapor pressures of CO.sub.2, a modified system technology and more pressure-resistant system components are necessary as compared with previous systems. Such systems are known, for example, from PCT patent application number WO 90/07683. In the event of traffic accidents, however, because of the high pressure level of CO.sub.2 in the circuit of the air-conditioning system, uncontrolled escape of CO.sub.2 may occur if system is damaged, which can result in a health hazard, especially to those within the vehicle.
In the event of any fire occurring and/or being caused by traffic accidents, especially in the engine compartment, fire extinguishing systems are provided for the motor vehicle, as are known for example from German Patent Document No. DE-GM 87 15 208.8. In that publication, the extinguishing system contains a container for the extinguishing agent and extinguishing lines which are guided to potential fire-hazard points in the engine compartment. Extinguishing takes placed, when needed, via crash or temperature sensors but can also be triggered manually. A special sensor system for this purpose has been disclosed in detail in European Patent Document EP-OS 487 445. Such extinguishing agent systems represent a substantial additional weight for the total weight of the vehicle, which entails an increased fuel consumption. Moreover, the extinguishing agent container occupies additional structural space which, especially in the case of small vehicles, is not available to a sufficient extent to permit the accommodation of such an extinguishing system.
An object of the invention is further to develop a motor vehicle of the generic type so that, in the event of a vehicle crash, a hazard to the occupants as a result of fire breaking out is avoided.
This object is achieved, according to the preferred embodiments of the invention, by utilizing the circulating medium as a fire extinguishing medium in the event of a fire breaking out in the motor vehicle.
By means of the invention, the circulating medium in the air-conditioning system is selectively utilized, when needed, in a simple manner and with economy of structural space as a fire extinguishing agent, or the air-conditioning system is used as a fire extinguishing sprinkler, there being no need for a separate store of extinguishing agent. In this arrangement, the extinguishing agent lines and the nozzles which terminate at the possible seats of fire represent only an insignificant additional weight for the vehicle. In the event of a crash and/or fire, a sensor system initiates an automatic fire extinguishing procedure, the emerging circulating medium, with fire-extinguishing capability, forcing out from the fire-hazard areas the atmospheric oxygen which is involved in originating and sustaining of the fire. Thus, controlled emergence of the circulating medium is possible both preventively, in order to avoid fire and fire injuries, and also actively to extinguish the fire at an existing source of fire, so that overall any danger to the vehicle occupants in the event of fire is avoided.